Byzantine units of measurement

Byzantine units of measurement were a combination and modification of the ancient Greek and Roman units of measurement used in the Byzantine Empire.

Until the reign of Justinian I (527–565), no universal system of units of measurement existed in the Byzantine world, and each region used its traditional measures. Justinian began the process of standardization that resulted in a specifically Byzantine system, chiefly due to the need of such a system for the fiscal administration. Official measurement and weighing was performed subject to an array of charges including the mestikon, miniatikon, zygastikon, kambaniatikon, gomariatikon, and samariatikon. Despite the central government's insistence on the use of official measures, other systems continued to be used in parallel, whether due to local traditions or foreign influences, or in order to cover the necessities of specific trades or crafts. In addition, from the 12th century, foreign merchants such as the Venetians, Pisans, and Genovese operating within the Empire received the right to use their own systems.

Length The Byzantine Empire continued to employ the anthropometric units used by the Greeks and Romans.

Weights and measures acts were sometimes undertaken by the emperors as forms of tax reform. An 11th-century guide to Byzantine tax collection contains emendations concerning the Emperor Michael's addition of a palm to the fathom used in computing the schoinion, an act which reduced the holders' taxable area by about 5%.

+Units of length Unit Greek name Greek feet meters Notes Digit(Finger) dáktylos () 0.0195 also called monas (), "unit", as the smallest unit of length. Palm palaistḗ () anticheir () 0.0787 Half-pousHalf-foot hēmipódion () 0.1574 Span spithamḗ () 0.2361 Pous(Foot) poûs () 1  0.3123 Derived from the ancient Greek foot, the standard foot length in Byzantium seems to have been 0.3123 m, but in practice the length fluctuated between 0.308 and 0.320 m Public Cubit dêmosios pêkhys () 0.4688  "forearm"The Public Cubit counted 24 daktyloi and was used mainly in construction, hence was also called lithikos ("stone"), [xylo]pristikos ("[wood]-sawing"), tektonikos ("builder's"). The Imperial or Geometric Cubit counted 32 daktyloi and was used for the measurement of fields for the purpose of tax assessment. Local variants also existed for various other commodities. Imperial or Geometric Cubit basilikos/geômetrikos pêkhys () 2  0.625 (Single) Pace bêma haploûn () 0.787 (=English pace) bêma diploûn () 5  1.574 (=Roman pace) Simple Orguia(Simple) Fathom haplê orguiá () 6  1.87Derived from the equivalent ancient Greek unit (1.89 m) From the 14th century on local variants also existed, often called kanna from the Italian canna. basilikê/geômetrikê orguiá () 2.10 9 spithamai = 108 daktyloi, used for the measurement of fields for the purpose of tax assessment. To ease the farmers' tax burden, Michael IV introduced a longer version of 9.25 spithamai (2.17 m) for use in middle and high quality, while the lower value was retained for poorer fields. Perch dekápodon () 10  3.148  "decafoot: 10-foot [length]" Schoinion skhoinion () 60 72  21.3025.30   "little schoenus"The basis of land tax assessments, variously reckoned as 10 fathoms in the fertile Balkan and west Anatolian themes and as 12 in the rest of Asia Minor. Plethron pléthron () 100  31.48 The Greek furlong, one side of the ancient Greek acreUncommon in Byzantine texts Stade stádion () 600  188.8 (=English furlong) Bowshot doxarioú bolḗ ()   Mile mílion ()     Also milion(=Roman mile) Schoenus skhoinos ()      "reed rope" stades, against various (usually longer) classical values Day's Journey hodós hēméras ()        

Area The ordinary units used for land measurement were Greek.

+Units of area Unit Greek name square Greek feet square meters Notes poûs () 1 0.095 Stremma strémma () 991   "turning" Sometimes described as a (square) "plethron", although this is uncommon in Byzantine texts The ancient Greek acre, originally defined by the distance plowed by a team of oxen in a day and continuing to vary according to land quality under the Byzantines between 900 and ModiosZeugarion módios () zeugárion ()   Highly variable. Modioi were sometimes much smaller units that might come 100 or 250 to a single zeugarion. The "Modion" was originally a grain measure, and "zeugarion" referred to a yoke.

Volume

The ordinary units used for liquid measurement were mostly Roman:

+Units of volume Unit Greek name Litras liters Notes (Liquid) Ounce ouggía () ogkía () ougkía () 0.1824 (=Roman uncia) CotylaHalf-xesta kotýlē () hēmixéstion () 0.276 (=Roman half-sextarius) Xesta xéstēs () 0.548 (=Roman sextarius) (Liquid) Litra(Liter) lítra () 1 2.1888 (=Roman libra) Handful phoûkta () 3.367 (Liquid) Modios módios () 40 87.552

Weight

The ordinary units used for measurement of weight or mass were mostly Roman, based on the late Roman pound. This has been reconstructed on the basis of known legislation of Constantine the Great in AD 309 establishing 72 gold solidi (, nómisma) to the pound. As the early solidi weighed 4.55 g, the pound was therefore 0.3276 kg at the time. The solidus was repeatedly debased, however, implying average pounds of 0.324 kg (4th–6th century), 0.322 kg (6th–7th century), 0.320 kg (7th–9th century), 0.319 kg (9th–13th century), and even less thereafter.

Model weights were made in lead, bronze, and glass and (less often) from gold and silver. They came in various styles. Presently, archaeologists believe the bronze spheres sliced flat at top and bottom and marked with an omicron/upsilon date from the early 3rd to late 5th centuries, gradually being replaced by cubes marked with a gamma/omicron (𐆄) over the course of the 4th century. In the second half of the 6th century, these were replaced by discs until at least the early 9th century and possibly the 12th. The glass weights had numerous advantages in manufacture and use but seem to have disappeared following the loss of the empire's Syrian and Egyptian provinces in the 7th century.

Analysis of the thousands of surviving model weights strongly suggest multiple local weight standards in the Byzantine Empire before the Arab conquests. Under Justinian, the weights of currency were administered by the and commodity weights by the praetorian prefect and eparch of the city. By the 9th century, the eparch nominally controlled all official weights in Constantinople, although archaeology has shown others issued their own weights, including proconsuls, , and in the west and anthypatoi, counts, and ephors in the east.

+Units of weight Unit Greek name Greek ounces grams Notes Scruple gramma () trēmísis () 1.55 Semissis sēmísis () 2.27 Nomisma nómisma () 4.55 Ounce ouggía () ogkía () ougkía () 1  27.3 (=Roman uncia) Litra(Pound) lítra () 12  327.6 Value , but diminishing over time.(=Roman pound)

See also Greek units Roman units

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